Quantitative muscle ultrasound detects disease progression in Duchenne muscular dystrophy

Abstract

Objective We assessed changes in quantitative muscle ultrasound data in boys with Duchenne muscular dystrophy (DMD) and healthy controls to determine if ultrasound can serve as a biomarker of disease progression. Two approaches were used: grey scale level (GSL), measured from the ultrasound image, and quantitative backscatter analysis (QBA) measured directly from the received echoes. Methods GSL and QBA were obtained from six unilateral arm/leg muscles in 36 boys with DMD and 28 healthy boys (age 2–14 years) for up to 2 years. We used a linear mixed-effects model with random intercept and slope terms to compare trajectories of GSL, QBA, and functional assessments. We analyzed separately a subset of boys who initiated corticosteroids. Results Compared to healthy boys, increasing GSL in DMD boys >7.0 years was first identified at 6 months (e.g., anterior forearm slope difference of 1.16 arbitrary units/month p=0.004, 95% confidence interval (CI) [0.38,1.94]); in boys ≤7 years, differences in GSL first appeared at 12 months (0.82 arbitrary units /month, p=0.04 95%CI [0.075,1.565] in rectus femoris). QBA performed similarly to GSL (e.g., DMD boys >7 years of 0.41dB/month, p=0.01, 95%CI [0.096,0.72] in anterior forearm at 6 months). US identified differences earlier than functional measures including 6-minute walk and supine-to-stand tests. However, neither QBA nor GSL showed an effect of corticosteroid initiation. Interpretation QBA performs similarly to GSL and both appear more sensitive than functional assessments for detecting muscle deterioration in DMD. Additional studies will be required to determine if quantitative muscle ultrasound can detect therapeutic efficacy.

Quantitative muscle ultrasound in upper extremity mononeuropathies

“…One approach simply relies upon measuring muscle thickness because atrophy reduces muscle bulk . The second approach is to quantify the echointensity of the muscle, which is expected to increase in most disorders as an increasing proportion of fat and connective tissue leads to increased reflectivity . Quantification of echointensity can be most easily performed by means of a gray scale level (GSL) analysis, in which an image is converted to a standard photo format, with the relative whiteness/darkness of the image obtained using a commercially available program.…”

“…Quantification of echointensity can be most easily performed by means of a gray scale level (GSL) analysis, in which an image is converted to a standard photo format, with the relative whiteness/darkness of the image obtained using a commercially available program. An alternative approach is to assess the direct backscatter of the acoustic signal; while this approach is likely to provide “truer” data, because it is not postprocessed by means of various proprietary algorithms, most commercial ultrasound systems do not provide such raw values . Regardless of the approach to quantification, performing such measurements of echointensity is not simple.…”

Electrical impedance myography in facioscapulohumeral muscular dystrophy: A 1‐year follow‐up study

“…It is still unclear which EIM variables are best suited to measure changes, and the choice for a specific variable depends on the disease being studied. Consequently, multiple studies have used different outcomes including, among others, single and multifrequency measures, single muscle and composite measures, single phase values, and phase ratios . Prior studies have shown that reactance is least susceptible to variability in subcutaneous fat content or electrode configuration .…”

“…For analyses, 4 different frequencies, 50, 100, 211, and 300 kH Z , were chosen on the basis of prior EIM studies in neuromuscular diseases. In addition, phase ratios were calculated for 50/211 kH Z and 100/300 kH Z …”

Guidelines for neuromuscular ultrasound training

“…Over the years, it has evolved into a distinct ultrasound subspecialty. A vast amount of literature provides evidence regarding the value of neuromuscular ultrasound in the diagnostic evaluation of neuromuscular disorders (more key references are provided in Data S1 online) . As a result, neuromuscular ultrasound has become a fundamental diagnostic tool in many electrodiagnostic labs, clinics, and radiology centers.…”